CN111989565B - Analysis method of silicon substrate - Google Patents
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- CN111989565B CN111989565B CN201980024689.2A CN201980024689A CN111989565B CN 111989565 B CN111989565 B CN 111989565B CN 201980024689 A CN201980024689 A CN 201980024689A CN 111989565 B CN111989565 B CN 111989565B
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- 239000000758 substrate Substances 0.000 title claims abstract description 386
- 238000004458 analytical method Methods 0.000 title claims abstract description 343
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 310
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 307
- 239000010703 silicon Substances 0.000 title claims abstract description 307
- 239000007788 liquid Substances 0.000 claims abstract description 143
- 238000001035 drying Methods 0.000 claims abstract description 72
- 239000002253 acid Substances 0.000 claims abstract description 64
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims abstract description 59
- 238000011084 recovery Methods 0.000 claims abstract description 48
- 239000003513 alkali Substances 0.000 claims abstract description 41
- 238000000034 method Methods 0.000 claims abstract description 32
- 238000010438 heat treatment Methods 0.000 claims abstract description 31
- 238000009616 inductively coupled plasma Methods 0.000 claims abstract description 18
- 238000007599 discharging Methods 0.000 claims abstract description 16
- 238000010408 sweeping Methods 0.000 claims abstract description 12
- 238000005070 sampling Methods 0.000 claims abstract description 7
- 238000000354 decomposition reaction Methods 0.000 claims description 50
- 239000007789 gas Substances 0.000 claims description 44
- 238000005530 etching Methods 0.000 claims description 31
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 26
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 25
- 229910017604 nitric acid Inorganic materials 0.000 claims description 25
- 238000011068 loading method Methods 0.000 claims description 17
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical group [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 15
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 15
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 10
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 8
- 239000002585 base Substances 0.000 claims description 8
- 229910052581 Si3N4 Inorganic materials 0.000 claims 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims 3
- 238000010129 solution processing Methods 0.000 claims 2
- 150000004767 nitrides Chemical class 0.000 abstract description 27
- 239000012535 impurity Substances 0.000 abstract description 22
- 238000001095 inductively coupled plasma mass spectrometry Methods 0.000 abstract description 16
- QOSATHPSBFQAML-UHFFFAOYSA-N hydrogen peroxide;hydrate Chemical compound O.OO QOSATHPSBFQAML-UHFFFAOYSA-N 0.000 abstract description 12
- 229910021654 trace metal Inorganic materials 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 129
- 239000012491 analyte Substances 0.000 description 22
- 239000012071 phase Substances 0.000 description 20
- 229910052751 metal Inorganic materials 0.000 description 19
- 239000002184 metal Substances 0.000 description 19
- 150000002739 metals Chemical class 0.000 description 18
- 239000012808 vapor phase Substances 0.000 description 15
- 239000000203 mixture Substances 0.000 description 9
- 150000003839 salts Chemical class 0.000 description 7
- 239000006199 nebulizer Substances 0.000 description 6
- 239000000460 chlorine Substances 0.000 description 5
- 229910052731 fluorine Inorganic materials 0.000 description 5
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 239000011737 fluorine Substances 0.000 description 3
- 229910000040 hydrogen fluoride Inorganic materials 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 229910003902 SiCl 4 Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 239000002210 silicon-based material Substances 0.000 description 2
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
- H01L22/10—Measuring as part of the manufacturing process
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- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
- H01L22/10—Measuring as part of the manufacturing process
- H01L22/12—Measuring as part of the manufacturing process for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/02—Elements
- C30B29/06—Silicon
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- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
- C30B33/08—Etching
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
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- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
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- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
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- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
- H01L21/321—After treatment
- H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
- H01L21/32133—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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Abstract
The application provides an analysis method of a silicon substrate, which can analyze trace metal impurities in the silicon substrate formed with a thick nitride film with high accuracy by ICP-MS. The analysis method of the present application uses an analysis device for a silicon substrate, which comprises: an analysis scanning port, an analysis liquid sampling mechanism and an analysis mechanism for performing inductively coupled plasma analysis; the analysis scan port includes: the method comprises the steps of carrying a silicon substrate with a nitride film formed thereon through a substrate analysis nozzle, sweeping the surface of the silicon substrate with a recovery liquid of a mixed liquid of hydrofluoric acid and hydrogen peroxide water through the substrate analysis nozzle, then discharging the recovery liquid onto the surface of the silicon substrate, heating and drying the silicon substrate, discharging a strong acid solution or a strong alkali solution, heating and drying the silicon substrate, sweeping the analysis liquid onto the surface of the silicon substrate, recovering the analysis liquid, and analyzing the analysis liquid by ICP-MS.
Description
Technical Field
The present application relates to an analysis method for analyzing impurities such as trace metals contained in a silicon substrate used for manufacturing semiconductors and the like. In particular, the present application relates to a method for analyzing a silicon substrate, which is suitable for analyzing a silicon substrate having a thick nitride film formed on the surface of the silicon substrate to be analyzed.
Background
In a silicon substrate such as a silicon wafer used for manufacturing a semiconductor, an analyzer capable of detecting impurities such as metals that affect the device characteristics is required with higher integration. As one of analysis methods capable of detecting even a very small amount of impurities such as metal in a silicon substrate, a method using an inductively coupled plasma mass spectrometry (ICP-MS) is known. In this analysis method, in order to take out impurities such as metals contained in a silicon substrate into a form that can be introduced into ICP-MS, the silicon substrate is etched by a vapor phase decomposition method, and the etched silicon substrate surface is swept (sweepping) with an analysis liquid, whereby the impurities such as metals are transferred to the analysis liquid, and the analysis liquid is introduced into ICP-MS and analyzed (for example, patent document 1). Further, patent document 2 discloses a method of analyzing impurities contained in a silicon substrate by using a nozzle for substrate analysis.
In such an analysis method, a technique of analyzing a silicon substrate on which a nitride film or an oxide film of silicon or the like having a relatively thick film thickness is formed has been proposed (for example, patent document 3). In the analysis method of patent document 3, a silicon substrate to be analyzed is subjected to a vapor phase decomposition treatment, and a high concentration recovery liquid, which is a mixture of 10 to 30 mass% hydrofluoric acid and 1 to 30 mass% hydrogen peroxide water, is swept over the surface of the silicon substrate through a nozzle for substrate analysis, and recovered, and the recovered high concentration recovery liquid is discharged onto the surface of the silicon substrate, and then the silicon substrate from which the high concentration recovery liquid has been discharged is dried by heating, and then the surface of the silicon substrate is swept over the analysis liquid through a nozzle for substrate analysis, whereby the analysis liquid of the transferred analysis object is subjected to an inductively coupled plasma analysis. According to this method, even in the case where a thick nitride film is formed on a silicon substrate, si (NH) generated when vapor-phase decomposition is performed with an etching gas of hydrogen fluoride can be suppressed 4 ) x F y Fluorine of (2)The influence of the ammonium white salt can be analyzed with high accuracy by ICP-MS. Further, the maintenance load of the analysis device can be reduced. Further, even when a thick oxide film is formed on a silicon substrate, si (OH) generated during vapor phase decomposition with a hydrogen fluoride etching gas can be suppressed 4 H and H 2 SiF 6 But can be analyzed with high accuracy by ICP-MS.
[ Prior Art literature ]
[ patent literature ]
Patent document 1: japanese patent laid-open No. 11-281542.
Patent document 2: japanese patent application laid-open No. 2013-257272.
Patent document 3: japanese patent publication No. 6108367.
Disclosure of Invention
[ problem to be solved by the application ]
However, when a silicon substrate is formed into a nitride film having a relatively large thickness (for example, 200nm or more), there is a case where analysis with high accuracy is not possible even by the above-described analysis method. This is because the nitride film formed on the silicon wafer is not ideal Si 3 N 4 Therefore, the white salt obtained by vapor phase decomposition with hydrofluoric acid is also undesirable Si (NH) 4 ) 2 F 6 In the form of (2), si (NH) 4 ) x F y Due to the morphology of (3). The chemical form of the ideal nitride film is Si 3 N 4 And the compound generated during the vapor phase decomposition of the etching gas with hydrofluoric acid is Si (NH) 4 ) 2 F 6 By mixing Si (NH) 4 ) 2 F 6 The heating will produce the following reaction, si can be used as SiF 4 The gas is reduced from the silicon substrate surface.
Si(NH 4 ) 2 F 6 →SiF 4 +2NH 4 F
However, the actual compound produced is Si (NH) 4 ) x F y When a nitride film having a thickness of 200nm or more is formed, the Si concentration in the analysis solution is 1000ppm or more even after heating in an excessive hydrofluoric acid state, and the formation cannot be performedHigh-precision analysis.
More specifically, according to the analysis method of patent document 3 of the prior art, the concentration of Si in 1mL of the analysis solution can be reduced to about 70ppm by using a high concentration recovery solution for a 12 inch silicon substrate on which a nitride film having a film thickness of 100nm is formed and drying the recovery solution, but Si remains at 1,000ppm or more when the nitride film thickness is 200 nm. The amount of Si to be removed varies depending on the amount of hydrofluoric acid used in the high concentration recovery liquid, and if the amount of hydrofluoric acid is small, 1,000ppm to 10,000ppm of Si remains in 1mL of the analysis liquid.
In view of the above, an object of the present application is to provide a method for analyzing a silicon substrate, which can analyze impurities such as trace metals contained in a nitride film with high accuracy by ICP-MS even in a silicon substrate having a nitride film with a film thickness of 200nm or more.
[ means for solving the problems ]
A first aspect of the present application is a method for analyzing a silicon substrate using an analysis device for a silicon substrate, the analysis device comprising: an analysis scanning port, an analysis liquid sampling mechanism, a nebulizer (nebulizer), and an analysis mechanism; the analysis scan port includes: a load port (load port) provided with a storage box storing a silicon substrate to be analyzed, a substrate transfer robot capable of taking out, transferring, and setting the silicon substrate stored in the load port, a drying chamber for heating and drying the silicon substrate, a vapor-phase decomposition chamber for etching the silicon substrate by an etching gas, an analysis table for placing the silicon substrate, and a nozzle for substrate analysis, the nozzle for substrate analysis being capable of sweeping the surface of the silicon substrate placed on the analysis table with an analysis liquid and recovering the analysis liquid of the transferred analysis object; the analysis liquid collection means includes an analysis container into which the analysis liquid collected by the nozzle for substrate analysis can be put; the sprayer sucks the analysis liquid put into the analysis container; the analysis means performs inductively coupled plasma analysis of the analysis liquid supplied from the atomizer; wherein a nitride film is formed on a silicon substrate, the silicon substrate is taken out from a loading port by a substrate conveying robot, the silicon substrate is conveyed to a gas phase decomposition chamber and is arranged, the gas phase decomposition treatment of the silicon substrate is carried out by etching gas in the gas phase decomposition chamber, the silicon substrate subjected to the gas phase decomposition treatment is conveyed to an analysis table of an analysis scanning port and is arranged on the analysis table, the surface of the silicon substrate is swept by a recovery liquid of a mixed liquid of hydrofluoric acid with concentration ranging from 1 mass% to 10 mass% and hydrogen peroxide water with concentration ranging from 1 mass% to 30 mass% through a nozzle for substrate analysis, the recovered recovery liquid is discharged to the surface of the silicon substrate, then the silicon substrate from which the recovery liquid is discharged is conveyed to a drying chamber and is arranged, the silicon substrate is heated and dried, the silicon substrate from which the heating and drying treatment are conveyed to the analysis table of the analysis scanning port and is arranged on the analysis table, and a strong acid solution or a strong alkali solution is discharged to the surface of the silicon substrate through the nozzle for substrate analysis; the method comprises the steps of conveying a silicon substrate from which a strong acid solution or a strong alkali solution is discharged to a drying chamber, setting the drying chamber, heating and drying the silicon substrate, conveying the heated and dried silicon substrate to an analysis table of an analysis scanning port, placing the analysis table, sweeping the surface of the silicon substrate with an analysis liquid through a nozzle for substrate analysis, and performing inductively coupled plasma analysis on the analysis liquid of the transferred analysis object.
First, a method for analyzing a silicon substrate according to a first aspect of the present application will be described. In analyzing a silicon substrate on which a nitride film having a relatively large thickness is formed, the silicon substrate taken out from a load port by a substrate transfer robot is first transferred to a vapor phase decomposition chamber and set in the chamber. Then, an etching gas containing hydrofluoric acid vapor is brought into contact with the silicon substrate to perform a vapor phase decomposition treatment. The silicon substrate subjected to the vapor phase decomposition treatment is transferred to an analysis table of an analysis scanning port by a substrate transfer robot and placed thereon. At this time, a recovery liquid of a mixture liquid of hydrofluoric acid having a concentration of 1 to 10 mass% and hydrogen peroxide water having a concentration of 1 to 30 mass% was poured into a substrate analysis nozzle of an analysis scanning port, and the surface of the silicon substrate was swept by a substrate analysis nozzle holding 1mL of the recovery liquid at the tip of the nozzle, thereby dissolving Si (NH 4 ) x F y Ammonium fluoride-based white salt of (a). In addition, impurities such as metals are mixed into the recovered liquid, and the impurities such as metals are used as residuesBut is present on the surface of the silicon substrate subjected to the vapor phase decomposition treatment.
Then, the recovery liquid recovered to the nozzle for substrate analysis is discharged back to the surface of the silicon substrate, and the recovery liquid is carried on a specific portion of the surface of the silicon substrate. When the silicon substrate loaded with the recovery liquid is transported to the drying chamber by the substrate transporting robot and set up, the silicon substrate is heated and dried at about 100 ℃, and Si (NH) contained in the recovery liquid 4 ) x F y Will decompose to some extent Si as SiF 4 The gas is removed, and NH is formed on the surface of the substrate 4 F and Si (NH) 4 ) x F y The white salt of (2) precipitates as a residue.
Then, the heated and dried silicon substrate is transported to an analysis stage of an analysis scanning port and placed thereon, and a strong acid solution or a strong alkali solution is discharged through a nozzle for substrate analysis. By discharging the strong acid solution and the strong alkali solution, si (NH) of the white salt in the nitride film is formed 4 ) x F y (NH) 4 ) x Reacts with strong acid or strong alkali, and is converted into a compound NH with better stability in the strong acid 4 NO 3 Etc., or in a strong base to NH 3 To make Si (NH) 4 ) x F y Si and F of (2) are liable to form SiF 4 . Thereafter, the silicon substrate from which the strong acid solution or the strong alkali solution has been discharged is transported to a drying chamber and set up, and is heated and dried, thereby obtaining SiF 4 Become a gas and evaporate. By this step, the Si component on the surface of the silicon substrate can be greatly reduced.
The silicon substrate heated and dried in the drying chamber is transported again to the analysis table by the substrate transport robot and placed thereon. At this time, 1mL of the analyte solution was poured into the substrate analysis nozzle, and then the surface of the silicon substrate was swept with the analyte solution to mix impurities into the analyte solution. The analysis liquid collected by the nozzle for substrate analysis is put into an analysis container in the analysis liquid collection means, and reaches the sprayer. Thereafter, the analysis liquid of the nebulizer was analyzed by ICP-MS. In this analysis solution, even a 12 inch silicon substrate having a nitride film with a film thickness of 200nm or more was formed, the concentration of Si in the analysis solution was still low (about 10 ppm). Therefore, according to the method for analyzing a silicon substrate of the present application, even a silicon substrate having a thick nitride film with a film thickness of 200nm or more can be analyzed by ICP-MS with high accuracy for impurities such as trace metals contained in the nitride film.
The strong acid solution and the strong alkali solution in the method for analyzing a silicon substrate of the present application are not particularly limited, and the strong acid is preferably any one or more of hydrofluoric acid, sulfuric acid, hydrochloric acid, and nitric acid, and the strong alkali is preferably potassium hydroxide or sodium hydroxide. The strong acid and the strong base can be 1 solution, or a mixed solution of multiple strong acids and a mixed solution of multiple strong bases. As for the concentration of the strong acid solution and the strong base solution, the drying time can be reduced by the solution which is not diluted as much as possible. In the present application, the concentration of the recovery liquid and the analysis liquid is preferably 1 to 10% by mass of hydrofluoric acid, and 1 to 30% by mass of hydrogen peroxide water.
According to the method for analyzing a silicon substrate of the present application, even a 12 inch silicon substrate having a thick nitride film of 200nm or more in thickness can be analyzed with high accuracy by ICP-MS while suppressing the influence of Si concentration, but when nitric acid is used as a strong acid, etching occurs on the surface of the silicon substrate. Therefore, in order to prevent the etching of the silicon substrate, the following analysis method of the silicon substrate was found as a second aspect of the present application.
A second aspect of the present application is an analysis method for a silicon substrate, using an analysis device for a silicon substrate, the analysis device for a silicon substrate including an analysis scanning port, an analysis liquid sampling mechanism, a nebulizer, and an analysis mechanism; the analysis scan port includes: a loading port provided with a storage box for storing a silicon substrate to be analyzed, a substrate transfer robot capable of taking out, transferring and setting the silicon substrate stored in the loading port, a drying chamber for heating and drying the silicon substrate, a gas phase decomposition chamber for etching the silicon substrate by etching gas, an analysis table for placing the silicon substrate, and a nozzle for substrate analysis, wherein the substrate transfer robot is capable of sweeping the surface of the silicon substrate placed on the analysis table with an analysis liquid and collecting the analysis liquid of the transferred analysis object; the analysis liquid collection means includes an analysis container into which the analysis liquid collected by the nozzle for substrate analysis can be put; the sprayer sucks the analysis liquid put into the analysis container; an analysis means for performing inductively coupled plasma analysis of the analysis liquid supplied from the atomizer; wherein a nitride film is formed on a silicon substrate, the silicon substrate is taken out from a loading port by a substrate transfer robot, the silicon substrate is transferred to a gas phase decomposition chamber and is set, and a gas phase decomposition treatment of the silicon substrate is performed in the gas phase decomposition chamber by etching gas; the method comprises the steps of conveying a silicon substrate subjected to gas phase decomposition treatment to an analysis table of an analysis scanning port, placing the silicon substrate, sweeping the surface of the silicon substrate with a recovery liquid of a mixed liquid of hydrofluoric acid with a concentration of 1 to 10 mass% and hydrogen peroxide with a concentration of 1 to 30 mass% through a nozzle for substrate analysis, recovering the recovered recovery liquid, discharging the recovered recovery liquid to the surface of the silicon substrate, conveying the silicon substrate subjected to discharge of the recovery liquid to a drying chamber, setting the silicon substrate, heating and drying the silicon substrate, conveying the heated and dried silicon substrate to an analysis table of the analysis scanning port, placing the silicon substrate, and discharging a strong acid solution or a strong alkali solution using an acid other than nitric acid on the surface of the silicon substrate through the nozzle for substrate analysis; conveying the silicon substrate from which the strong acid solution or the strong alkali solution using the acid other than nitric acid is discharged to a drying chamber, setting the drying chamber, heating and drying the drying chamber, conveying the heated and dried silicon substrate to an analysis table of an analysis scanning port again, placing the analysis table, and discharging the strong acid solution or the strong alkali solution on the surface of the silicon substrate through a nozzle for substrate analysis; the method comprises the steps of conveying a silicon substrate from which a strong acid solution or a strong alkali solution is discharged to a drying chamber, setting the drying chamber, heating and drying the silicon substrate, conveying the heated and dried silicon substrate to an analysis table of an analysis scanning port, placing the analysis table, sweeping the surface of the silicon substrate with an analysis liquid through a nozzle for substrate analysis, and performing inductively coupled plasma analysis on the analysis liquid of the transferred analysis object.
In a second aspect of the present application, after the treatment with the recovery liquid in the first aspect of the present application, the treatment with the strong acid solution or the strong alkali solution is performed for the second time in the following manner: firstly, a strong acid solution or a strong alkali solution using an acid other than nitric acid is discharged on the surface of a silicon substrate treated with a recovery liquid, and the silicon substrate is heated and dried; then, the strong acid solution (the acid constituting the strong acid solution also includes nitric acid) or the strong alkali solution is discharged again and heated and dried; then, the sample is swept with the analyte.
When the strongly acidic solution using nitric acid is discharged to the surface of the silicon substrate after the treatment with the recovery liquid, hydrogen fluoride remaining on the surface of the silicon substrate is mixed with nitric acid, and thus the silicon substrate is etched by the reaction described below.
6HF+4HNO 3 +Si→H 2 SiF 6 +4NO 2 +4H 2 O
Therefore, in the second aspect of the present application, after the treatment with the recovery liquid, a strong acid solution or a strong alkali solution using an acid other than nitric acid is discharged, and the silicon substrate surface is heated and dried, whereby a Si component is removed to some extent as a first treatment. Then, the strong acid solution or the strong alkali solution is discharged again on the surface of the silicon substrate, and the silicon substrate is heated and dried, so that the Si component on the surface of the silicon substrate is greatly reduced, and the silicon substrate is treated for the second time. According to the analysis method of the silicon substrate of the second aspect of the present application, although the Si component of the silicon substrate surface is greatly reduced, etching of the silicon substrate surface can be suppressed.
In the second aspect of the present application, any one or more of hydrofluoric acid, sulfuric acid, and hydrochloric acid may be used as the acid other than nitric acid constituting the strong acid solution for the first treatment; the strong base solution may use potassium hydroxide and/or sodium hydroxide. Further, as the acid constituting the strong acid solution for the second treatment, any one or more of hydrofluoric acid, sulfuric acid, hydrochloric acid, and nitric acid may be used; the strong base solution may use potassium hydroxide and/or sodium hydroxide.
As another method of the second aspect of the present application, the present inventors have further found a method of analyzing a silicon substrate (third aspect of the present application) as described below. A third aspect of the present application is a method for analyzing a silicon substrate, comprising the steps of: an analysis scanning port, an analysis liquid sampling mechanism, a sprayer and an analysis mechanism; the analysis scan port includes: a loading port provided with a storage box for storing a silicon substrate to be analyzed, a substrate transfer robot capable of taking out, transferring and setting the silicon substrate stored in the loading port, a drying chamber for heating and drying the silicon substrate, a gas phase decomposition chamber for etching the silicon substrate by etching gas, an analysis table for placing the silicon substrate, and a nozzle for substrate analysis, wherein the substrate transfer robot is capable of sweeping the surface of the silicon substrate placed on the analysis table with an analysis liquid and collecting the analysis liquid of the transferred analysis object; the analysis liquid collection means includes an analysis container into which the analysis liquid collected by the nozzle for substrate analysis can be put; the sprayer sucks the analysis liquid put into the analysis container; the analysis means performs inductively coupled plasma analysis of the analysis liquid supplied from the atomizer; wherein a nitride film is formed on a silicon substrate, the silicon substrate is taken out from a loading port by a substrate transfer robot, the silicon substrate is transferred to a gas phase decomposition chamber and is set, and a gas phase decomposition treatment of the silicon substrate is performed in the gas phase decomposition chamber by etching gas; performing first solution treatment: conveying the silicon substrate subjected to gas phase decomposition treatment to an analysis table of an analysis scanning port, placing the silicon substrate, discharging a strong acid solution or a strong alkali solution on the surface of the silicon substrate through a nozzle for substrate analysis, conveying the silicon substrate discharged with the strong acid solution or the strong alkali solution to a drying chamber, arranging the silicon substrate, and heating and drying the silicon substrate; and (3) performing second solution treatment: conveying the silicon substrate which is heated and dried by the first solution treatment to an analysis table of an analysis scanning port, placing the analysis table, discharging a strong acid solution or a strong alkali solution which is different from the first solution treatment on the surface of the silicon substrate through a nozzle for substrate analysis, conveying the silicon substrate which is discharged the strong acid solution or the strong alkali solution which is different from the first solution treatment to a drying chamber, arranging the drying chamber, and heating and drying the silicon substrate; the heated and dried silicon substrate treated with the second solution is transported to an analysis stage of an analysis scanning port and placed thereon, and the surface of the silicon substrate is swept with an analysis liquid by a nozzle for substrate analysis, whereby inductively coupled plasma analysis is performed on the analysis liquid from which the analysis target has been transferred.
The method for analyzing a third-state silicon substrate according to the present application is described herein. Here, only the differences from the analysis method of the silicon substrate according to the second aspect of the present application will be described.
In the analysis method of the third aspect of the present application, the solution treatment of 2 stages is performed after the vapor phase decomposition treatment, instead of the treatment with the recovery liquid of hydrofluoric acid and hydrogen peroxide water. That is, in the third aspect of the present application, the following first solution treatment is performed: and (3) discharging a strong acid solution or a strong alkali solution on the surface of the silicon substrate subjected to the gas phase decomposition treatment, conveying the silicon substrate discharged with the strong acid solution or the strong alkali solution to a drying chamber, setting the drying chamber, and heating and drying the silicon substrate. Then, the following second solution treatment was performed: and discharging a strong acid solution or a strong alkali solution different from the first solution treatment on the surface of the silicon substrate subjected to the first solution treatment, and conveying the silicon substrate subjected to the discharge of the strong acid solution or the strong alkali solution different from the first solution treatment to a drying chamber, setting the silicon substrate, and heating and drying the silicon substrate. Then, the surface of the silicon substrate is swept with the analyte solution, and inductively coupled plasma analysis is performed on the analyte solution from which the analyte has been transferred.
The third aspect of the present application will be specifically described by taking as an example the case of using hydrochloric acid as the strong acid for the first solution treatment and nitric acid as the strong acid for the second solution treatment. After the gas phase decomposition treatment, if hydrochloric acid solution is used for the first solution treatment, a part of Si component becomes Si (NH) 4 ) x Cl y In the form of (a), a certain amount of the Si component is evaporated by the subsequent heat drying. The higher the hydrochloric acid concentration, the higher the capability of removing Si components becomes. The main cause of etching a silicon substrate is the mixing of fluorine (F) ions and an oxidizing agent. On the other hand, hydrochloric acid is a reducing agent, and etching of the silicon substrate can be suppressed by replacing fluorine (F) ions with chlorine (Cl) ions. Thereafter, if a nitric acid solution is used for the second solution treatment, si (NH) 4 ) x F y With Si (NH) previously generated from hydrochloric acid solution 4 ) x Cl y (NH) in the mixed salt of (2) 4 ) x Cl y And (NH) 4 ) x F y Part is converted into (NH) by nitric acid 4 ) x NO 3 To easily generate SiF 4 SiCl 4 . Thereafter, the silicon substrate from which the nitric acid solution was discharged is conveyedTo a drying chamber and heating and drying the SiF 4 SiCl 4 And is vaporized as a gas. By the aforementioned step of using the hydrochloric acid solution and the step of using the nitric acid solution, the Si component on the surface of the silicon substrate can be greatly reduced. In addition, the third aspect of the present application provides a method for analyzing a silicon substrate, which can suppress etching of the surface of the silicon substrate. At this time, the efficiency of removing Si of nitric acid having a high concentration is high in terms of the nitric acid concentration.
In the first aspect of the present application to the third aspect of the present application, the concentration of the strong acid solution or the strong alkali solution is preferably as follows. The concentration indicated here is the mass concentration when each drug is used alone. The strong acid is 18% to 36% when hydrochloric acid, 34% to 68% when nitric acid, 1% to 38% when hydrofluoric acid, and 1% to 10% when sulfuric acid; the strong base is 1 to 50% in the case of potassium hydroxide and 1 to 30% in the case of sodium hydroxide. In addition, when a plurality of kinds of the solutions are mixed for use, the solutions can be prepared by appropriately adjusting the solutions.
In the analysis method of a silicon substrate of the present application, the heating temperature at the time of heat drying is preferably set to 100 to 130 ℃. If the temperature exceeds 130 ℃, impurities such as metals tend to be evaporated together during evaporation. If the temperature is less than 100 ℃, it takes a long time to heat and dry the silicon substrate, and the liquid component existing on the silicon substrate cannot be reliably evaporated.
[ efficacy of the application ]
As described above, according to the method for analyzing a silicon substrate of the present application, even a silicon substrate having a thick nitride film with a film thickness of 200nm or more can be analyzed by ICP-MS with high accuracy for impurities such as trace metals contained in the nitride film.
Drawings
Fig. 1 is a schematic view of an analysis device for a silicon substrate.
Fig. 2 is a schematic cross-sectional view of a nozzle for substrate analysis.
Detailed Description
Hereinafter, embodiments of the present application will be described with reference to the drawings. Fig. 1 is a schematic view of an analysis device for a silicon substrate according to the present embodiment. The analysis device 1 for a silicon substrate of fig. 1 is composed of the following components: a loading port 10 provided with a not-shown housing box for housing the silicon substrate W to be analyzed; a substrate transfer robot 20 capable of taking out, transferring, and setting a silicon substrate W; an aligner 30 for adjusting the position of the silicon substrate; a gas phase decomposition chamber 40 for etching the silicon substrate W; a drying chamber 50 for heating and drying treatment; an analysis stage 61 on which a silicon substrate W is placed; a substrate analysis nozzle 62 for sweeping and collecting an analysis liquid on the surface of the silicon substrate placed on the analysis stage 61; a nozzle operation robot 63 for operating the substrate analysis nozzle 62; an analysis scan port 60; an automatic sampler 70 (analysis liquid collection means) provided with an analysis container (not shown) into which the high-concentration recovery liquid and the analysis liquid recovered by the substrate analysis nozzle 62 can be put; a nebulizer (not shown); and inductively coupled plasma analyzer (ICP-MS) 80 for inductively coupled plasma analysis. The analysis scanning port 60 is provided with a recovery liquid, a strong acid solution, a strong alkali solution, and an analysis liquid according to the analysis method.
Fig. 2 is a schematic cross-sectional view of the nozzle 62 for substrate analysis. The substrate analysis nozzle 62 is operated by a nozzle operation robot (not shown) to fill, suck, and discharge a solution such as an analysis solution into the liquid storage portion 622 of the nozzle body 621. For example, when the surface of the silicon substrate is swept by the analysis liquid D, the analysis liquid is held by a dome-shaped solution holding portion 623 provided at the tip of the nozzle body 621, and is thereby brought into contact with the surface of the silicon substrate W, and the nozzle operation robot is operated to move the analysis liquid D on the surface of the silicon substrate, whereby impurities such as trace metals to be analyzed are transferred to the analysis liquid.
Next, the procedure of analysis performed by the analysis device for a silicon substrate according to the present embodiment will be described. The method for analyzing a silicon substrate according to the first aspect of the present application will be described as an example. The second and third samples of the present application can be prepared by appropriately matching the analysis sequence and operating the analysis device for a silicon substrate.
First, the substrate transfer robot 20 takes out the silicon substrate W to be analyzed from the load port 10, and transfers the silicon substrate W to the aligner 30 provided in the apparatus to adjust the position of the silicon substrate W. Thereafter, the silicon substrate W is transported to the gas-phase decomposition chamber 40 and placed in the chamber.
In the vapor phase decomposition chamber 40, an etching gas containing hydrofluoric acid vapor is blown onto the silicon substrate W, and etching of the silicon substrate surface is performed to perform vapor phase decomposition treatment. By this vapor phase decomposition treatment, impurities such as metals and silicon-containing compounds contained in the film of the nitride film on the surface of the silicon substrate remain as residues on the silicon substrate.
The silicon substrate W after the gas phase decomposition treatment is carried to the analysis table 61 and placed thereon. Then, the nozzle operation robot 63 is operated to fill the substrate analysis nozzle 62 with the recovery liquid recovered from the analysis scanning port 60. The substrate analysis nozzle 62 filled with the recovery liquid is moved onto the silicon substrate, a part of the solution is discharged onto the silicon substrate, and the front end of the nozzle body is scanned over the surface of the silicon substrate W while the recovery liquid is held. Accordingly, impurities such as metals and silicon-containing compounds remaining as residues on the silicon substrate are mixed into the recovery liquid. After sweeping with the recovery liquid, the entire amount of the recovery liquid recovered to the substrate analysis nozzle 62 is discharged onto the silicon substrate. The discharge point in this case may be one point or may be divided into a plurality of points.
The silicon substrate W on which the recovery liquid is placed is transported to the drying chamber 50 and placed therein. Then, the silicon substrate W is heat-dried at a temperature of 100 ℃ to 130 ℃. The drying chamber 50 is heated and dried to deposit a product such as a white salt on the silicon substrate.
The heated and dried silicon substrate W is transported to the analysis table 61 by the substrate transport robot 20 and placed thereon. Then, the nozzle operation robot 63 is operated, and the substrate analysis nozzle 62 is filled with the strong acid solution or the strong alkali solution through the analysis scanning port 60. The substrate analysis nozzle 62 discharges a strong acid solution or a strong alkali solution onto the silicon substrate. The silicon substrate W from which the strong acid solution or the strong alkali solution is discharged is transported to the drying chamber 50 and placed therein. Then, the silicon substrate W is heat-dried at a temperature of 100 ℃ to 130 ℃. By the heating and drying in the drying chamber 50, silicon (Si) existing on the silicon substrate is converted into SiF 4 The gas is volatilized and removed.
The silicon substrate W after the heat drying is transported to the analysis table 61 by the substrate transport robot 20 and placed thereon. Then, the nozzle operation robot 63 is operated, and the substrate analysis nozzle 62 is filled with the analysis liquid through the analysis scanning port 60. The nozzle for substrate analysis filled with the analyte liquid moves onto the silicon substrate W and discharges a part of the analyte liquid, and the front end of the nozzle body is scanned over the surface of the silicon substrate W while the analyte liquid is held. Accordingly, impurities such as metals remaining as residues on the silicon substrate W are mixed into the analysis liquid. The sweep using the analyte solution can be performed in accordance with the discharge point of the recovered solution. For example, when the recovery liquid is discharged at one place, the recovery liquid may be swept in the vicinity of the discharge place, and when the recovery liquid is discharged at a plurality of places, the recovery liquid may be swept over the entire surface of the silicon substrate W.
The analysis liquid, which is swept over the surface of the silicon substrate W and mixed with impurities, is put into an analysis container (not shown) provided in an automatic sampler (analysis liquid collection means) 70, and the analysis container is called a PTFE sample bottle (real). The analysis solution in the analysis container was sucked up by a nebulizer and analyzed by ICP-MS.
Example 1: then a nitride film (Si) having a film thickness of 200nm was formed X N y ) The results of analysis of a 12 inch diameter silicon substrate are illustrated. The recovery liquid used was a mixture (1000. Mu.L) of 3% strength by mass hydrofluoric acid and 4% strength by mass hydrogen peroxide water. The strong acid solution used 68% by mass of nitric acid, and the analysis solution used a mixture of 3% by mass of hydrofluoric acid and 4% by mass of hydrogen peroxide water. Furthermore, the ICP-MS of the analyzer was manufactured by Perkinelmer company as ELAN DRC II. In addition, this embodiment 1 corresponds to the first aspect of the present application.
Comparative example 1: a nitride film (Si) having a film thickness of 200nm was formed by the analysis method of patent document 3 x N y ) The results of analysis of a 12 inch diameter silicon substrate are illustrated. As the high concentration recovery liquid, a mixture (1000. Mu.L) of 20% by mass hydrofluoric acid and 15% by mass hydrogen peroxide water was used. The analysis liquid used was a mixture of 3% by mass hydrofluoric acid and 4% by mass hydrogen peroxide. In patent document 3, the entire surface of the silicon substrate is swept with an analyte solution, and the analyte solution is mixedImpurities such as metals were introduced, and the Si concentration in 1ml of the collected analysis solution was found to be about 1000ppm.
Analysis was performed under the conditions of example 1, and the results were: the entire surface of the silicon substrate was swept with the analyte solution, and impurities such as metals were mixed into the analyte solution, and the concentration of Si in 1mL of the recovered analyte solution was found to be about 10ppm, which was very low. Further, the surface of the silicon substrate after the analysis liquid was collected was observed, and it was confirmed that a part of the surface was etched.
Example 2: in this example 2, the same silicon substrate as in example 1 was analyzed by the analysis method corresponding to the second aspect of the present application, and the results thereof will be described. The recovery liquid used was a mixture (1000. Mu.L) of 3% strength by mass hydrofluoric acid and 4% strength by mass hydrogen peroxide water. Further, 36% hydrochloric acid was used as the first strong acid solution, and 68% nitric acid was used as the second strong acid solution. The analysis liquid used was a mixture of 3% by mass hydrofluoric acid and 4% by mass hydrogen peroxide water. The analysis apparatus, the heat drying temperature, and the like were the same as those in example 1.
The results of the analysis under the conditions of example 2 were: the entire surface of the silicon substrate was swept with the analyte solution, and impurities such as metals were mixed into the analyte solution, so that the concentration of Si in 1mL of the recovered analyte solution was adjusted to be about 10ppm, which was very low. Then, the surface of the silicon substrate after the analysis liquid was collected was observed, and almost no etched portion was observed.
Example 3: in example 3, the same silicon substrate as in example 1 was analyzed by the analysis method corresponding to the third sample of the present application, and the results thereof will be described.
In this example 3, a 36 mass% hydrochloric acid solution (1000. Mu.L) was used as a recovery solution of the first solution, and a 68 mass% nitric acid solution (1 mL) was used as the second solution. The analysis liquid used was a mixture of 3% by mass hydrofluoric acid and 4% by mass hydrogen peroxide water. The analytical apparatus, the heat drying temperature, and the like were the same as in example 1.
The results of the analysis under the conditions of example 3 were: the entire surface of the silicon substrate was swept with the analyte solution, and impurities such as metals were mixed into the analyte solution, so that the concentration of Si in 1ml of the recovered analyte solution was adjusted to be about 10ppm, which was very low. Then, the surface of the silicon substrate after the analysis liquid was collected was observed, and almost no etched portion was observed.
Description of the reference numerals
1. Analysis device for silicon substrate
10. Load port
20. Substrate transfer robot
30. Alignment device
40. Gas phase decomposition chamber
50. Drying chamber
60. Analytical scan port
70. Automatic sampler
80. Inductively coupled plasma analyzer
D analysis liquid
A W silicon substrate.
Claims (6)
1. A method for analyzing a silicon substrate, wherein an analysis device for a silicon substrate is used, the analysis device for a silicon substrate comprising: an analysis scanning port, an analysis liquid sampling mechanism, a sprayer and an analysis mechanism; the analysis scan port has: a loading port provided with a storage box for storing a silicon substrate to be analyzed, a substrate transfer robot capable of taking out and transferring the silicon substrate stored in the loading port, a drying chamber for heating and drying the silicon substrate, a gas-phase decomposition chamber for etching the silicon substrate by etching gas, an analysis table for placing the silicon substrate, and a nozzle for substrate analysis for collecting the analysis liquid of the transferred analysis object; the analysis liquid collection means includes an analysis container into which the analysis liquid collected by the nozzle for substrate analysis can be put; the sprayer sucks the analysis liquid put into the analysis container; the analysis mechanism performs inductively coupled plasma analysis on the analysis liquid supplied by the sprayer;
wherein a silicon nitride film having a thickness of 200nm or more is formed on a silicon substrate,
taking out the silicon substrate from the loading port by a substrate conveying robot, conveying the silicon substrate to a gas-phase decomposition chamber, and performing gas-phase decomposition treatment of the silicon substrate by etching gas in the gas-phase decomposition chamber;
the method comprises the steps of conveying a silicon substrate subjected to gas phase decomposition treatment to an analysis table of an analysis scanning port, placing the silicon substrate, sweeping the surface of the silicon substrate through a nozzle for substrate analysis by using a recovery liquid of a mixed liquid of hydrofluoric acid with a mass concentration of 1% to 10% and hydrogen peroxide with a mass concentration of 1% to 30%, recovering the silicon substrate, and discharging the recovered recovery liquid to the surface of the silicon substrate;
then, the silicon substrate from which the recovered liquid was discharged is transported to a drying chamber, and heated and dried;
conveying the heated and dried silicon substrate to an analysis table of an analysis scanning port, placing the substrate, and discharging a strong acid solution or a strong alkali solution on the surface of the silicon substrate through a nozzle for substrate analysis;
conveying the silicon substrate from which the strong acid solution or the strong alkali solution is discharged to a drying chamber, and heating and drying the silicon substrate;
the heated and dried silicon substrate is transported to an analysis table of an analysis scanning port and placed thereon, and the surface of the silicon substrate is swept with an analysis liquid by a nozzle for substrate analysis, whereby inductively coupled plasma analysis is performed on the analysis liquid from which the analysis target has been transferred.
2. A method for analyzing a silicon substrate, wherein an analysis device for a silicon substrate is used, the analysis device for a silicon substrate comprising: an analysis scanning port, an analysis liquid sampling mechanism, a sprayer and an analysis mechanism; the analysis scan port has: a loading port provided with a storage box for storing a silicon substrate to be analyzed, a substrate transfer robot capable of taking out and transferring the silicon substrate stored in the loading port, a drying chamber for heating and drying the silicon substrate, a gas-phase decomposition chamber for etching the silicon substrate by etching gas, an analysis table for placing the silicon substrate, and a nozzle for substrate analysis for collecting the analysis liquid of the transferred analysis object; the analysis liquid collection means includes an analysis container into which the analysis liquid collected by the nozzle for substrate analysis can be put; the sprayer sucks the analysis liquid put into the analysis container; the analysis mechanism performs inductively coupled plasma analysis on the analysis liquid supplied by the sprayer;
wherein a silicon nitride film of 200nm or more is formed on a silicon substrate,
taking out the silicon substrate from the loading port by a substrate conveying robot, conveying the silicon substrate to a gas-phase decomposition chamber, and performing gas-phase decomposition treatment of the silicon substrate by etching gas in the gas-phase decomposition chamber;
the method comprises the steps of conveying a silicon substrate subjected to gas phase decomposition treatment to an analysis table of an analysis scanning port, placing the silicon substrate, sweeping and recovering the silicon substrate surface with a recovery liquid of a mixed liquid of hydrofluoric acid with a mass concentration of 1% to 10% and hydrogen peroxide with a mass concentration of 1% to 30% through a nozzle for substrate analysis, and discharging the recovered recovery liquid to the silicon substrate surface;
then, the silicon substrate from which the recovered liquid was discharged is transported to a drying chamber, and heated and dried;
transporting the heated and dried silicon substrate to an analysis table of an analysis scanning port, placing the substrate, and discharging a strong acid solution or a strong alkali solution using an acid other than nitric acid on the surface of the silicon substrate through a nozzle for substrate analysis;
conveying the silicon substrate from which the acid solution or the strong alkali solution other than nitric acid is discharged to a drying chamber, and heating and drying the silicon substrate;
then, the heated and dried silicon substrate is conveyed to an analysis table of an analysis scanning port again and is placed, and a strong acid solution or a strong alkali solution is discharged from the surface of the silicon substrate through a nozzle for substrate analysis;
conveying the silicon substrate from which the strong acid solution or the strong alkali solution is discharged to a drying chamber, and heating and drying the silicon substrate;
the heated and dried silicon substrate is transported to an analysis table of an analysis scanning port and placed thereon, and the surface of the silicon substrate is swept with an analysis liquid by a nozzle for substrate analysis, whereby inductively coupled plasma analysis is performed on the analysis liquid from which the analysis target has been transferred.
3. A method for analyzing a silicon substrate, wherein an analysis device for a silicon substrate is used, the analysis device for a silicon substrate comprising: an analysis scanning port, an analysis liquid sampling mechanism, a sprayer and an analysis mechanism; the analysis scan port has: a loading port provided with a storage box for storing a silicon substrate to be analyzed, a substrate transfer robot capable of taking out and transferring the silicon substrate stored in the loading port, a drying chamber for heating and drying the silicon substrate, a gas-phase decomposition chamber for etching the silicon substrate by etching gas, an analysis table for placing the silicon substrate, and a nozzle for substrate analysis for collecting the analysis liquid of the transferred analysis object; the analysis liquid collection means includes an analysis container into which the analysis liquid collected by the nozzle for substrate analysis can be put; the sprayer sucks the analysis liquid put into the analysis container; the analysis mechanism performs inductively coupled plasma analysis on the analysis liquid supplied by the sprayer;
wherein a silicon nitride film of 200nm or more is formed on a silicon substrate,
taking out the silicon substrate from the loading port by a substrate conveying robot, conveying the silicon substrate to a gas-phase decomposition chamber, and performing gas-phase decomposition treatment of the silicon substrate by etching gas in the gas-phase decomposition chamber;
performing first solution treatment: conveying the silicon substrate subjected to gas phase decomposition treatment to an analysis table of an analysis scanning port, placing the silicon substrate, discharging a strong acid solution or a strong alkali solution on the surface of the silicon substrate through a nozzle for substrate analysis, conveying the silicon substrate discharged with the strong acid solution or the strong alkali solution to a drying chamber, and heating and drying the silicon substrate;
and (3) performing second solution treatment: conveying the silicon substrate which is processed by the first solution and heated and dried to an analysis table of an analysis scanning port, placing the analysis table, discharging a strong acid solution or a strong alkali solution which is different from the first solution processing on the surface of the silicon substrate through a nozzle for substrate analysis, conveying the silicon substrate which is discharged the strong acid solution or the strong alkali solution which is different from the first solution processing to a drying chamber, and heating and drying the silicon substrate;
the silicon substrate heated and dried by the second solution treatment is carried to an analysis table of an analysis scanning port and placed thereon, and an analysis liquid of the transferred analysis object is scanned over the surface of the silicon substrate by a nozzle for substrate analysis, and inductively coupled plasma analysis is performed on the analysis liquid.
4. The method for analyzing a silicon substrate according to any one of claims 1 to 3, wherein the strong acid is at least one of hydrofluoric acid, sulfuric acid, hydrochloric acid, and nitric acid, and the strong base is potassium hydroxide and/or sodium hydroxide.
5. The method for analyzing a silicon substrate according to any one of claims 1 to 3, wherein a heating temperature at the time of heat drying is 100℃to 130 ℃.
6. The method for analyzing a silicon substrate according to claim 4, wherein the heating temperature at the time of heat drying is 100℃to 130 ℃.
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| JP6603934B2 (en) | 2019-11-13 |
| KR102470897B1 (en) | 2022-11-25 |
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